Don't let him get away ... Roosters coach Trent Robinson sees how valuable Sonny Bill Williams is to the NRL.

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Sydney Roosters coach Trent Robinson has implored the NRL not to let Sonny Bill Williams become the next Israel Folau, but rugby league's prodigal son says he is in no hurry to make a call on his future.

Williams put on another masterclass as the Roosters moved up to second spot on the ladder with an 18-12 win over Manly on Monday night, the former All Black having taken the NRL by storm since returning to the code.

But having watched Folau - who this year shunned the NRL when salary cap complications made a move to Parramatta too hard - star in his first two appearances for the Wallabies, Robinson made an impassioned plea for the league not to make the same mistake twice.

"Sonny's added huge value to the Roosters and also to our game," Robinson said.

"Even I'm switching over and watching Israel Folau play.

"We're all enjoying watching him play - there's a sense of pride when he plays well for every rugby league supporter.

"We don't want that to happen Sonny ... going to watch him play with another code.

While it has been widely expected Williams would return for a second season with the Roosters in 2014 before a possible return to rugby union ahead of the 2015 World Cup, Robinson said there had been no discussions between the dual international and the club.

Williams said he had no timeframe on when he would make a call.

"Still no talks at the moment," Williams said concerning a new contract.

"For me, I just keep humble, keep working hard.

"I know that if I do the business on the field things will happen off it and fall into place.

"I just keep it simple like that.

"I don't worry about the salary cap ... I just do my thing, work hard and try and earn the boys' respect through how I play or how I carry myself."

Robinson said he would not try to force anything either.

"I'm not putting pressure on it because I know there's going to be a lot of pressure from outside," he said.

"I'm coaching him for the time that he's here and that's this season at the moment.

"We definitely hope he decides to stick around but we haven't even talked about it yet."